Highway crossing protection



Patented Apr. 11, 1939 UNITED STATES PATENT OFFICE HIGHWAY CROSSING PROTECTION Application July 9, 1936, Serial No. 89,722

9 Claims.

My invention relates to highway crossing protection; that is, to appara-tus for protecting the intersections of railways and highways.

I will'describe three forms of apparatusem bodying my invention, and will then point out the novel features thereof in claims;

'Inthe accompanying drawing, Fig. 1 is a dia-' grammatic view showing one form of apparatus embodying 'myinvention. Figs. 2 and 3 are diagrammatic views showing modified forms of the apparatus ofFig. 1, and also embodying my invention.

Similar reference characters refer to similar parts in each of the views.

I Referring first to Fig. 1, the reference characters I and la designate the track rails of a railway over which traflic moves in both directions. Theserails are divided by insulated joints 2 to form two track circuit sections having, normally,

an effective length defined by the distance DE and- F-G. These track circuits, at times, have aneffectivelengthD-F and E-G, respectively, as will be explainedhereinafter. A highway 1-1 intersects the railway track between the rail joints at E and F.

The left-hand section of track is provided with atrackcircuit comprising a source of current 3 and the winding of a track relay TRI This circuit may be traced from the positive terminal of source 3 at location D, through rail I, wires 4 and 5, winding of relay TRI, wire 6. front contact 18 of relay XRZ, wire 42, and rail la, to the negative terminal of source 3. The right-hand section of track is provided with a similar track circuit including a second source 3 at location G and the Winding of the track relay TR2. This circuit may be traced from the positive terminal ofsource 3, through rail I, wire it], front contact "-12 of relay XRI, wire l3, winding'of relay "I'R2, wires I4 and I5, and rail la, back to the negative terminal of source 3.

Relay XR, which comprises the right-hand and left-hand magnets X32 and XRI, is the usual interlocking relay and may be of any suitable 5 type, such, for example, as the relay shown in United States Letters Patent No. 1,799,629, granted to W. K. Lockhart and T. J. OMeara on April '7, 1931. This typeof relay is well known and is characterized by the fact that when the left-hand magnet XRI is deenergized, the downward movement of the armature associated therewith operates a mechanical locking device which keeps the armature associated with the right-hand magnet XRI locked up in approximately its Elli mid-position, whereby the back contacts 'l9 and IG -I'I remain open. Similarly, if the righthand-magnet-XRIis the first to become deenergized, then back contacts lI--I3 and I8l9 are prevented from closing, even though magnet XRI becomes subsequently deenergized. Front contacts 1-43 and I ll2 have, what I shall term, the flagman adjustment. That is, these contacts remain closed when the associated armature is in the locked up position. The interlocking relay XR controls a highway crossing sig- 10 nal S which may be of any suitable type but which, as hereshown, is a bell. Signal S becomes energized over an obvious circuit whenever either back contact lG-I'l or Iii-I9 becomes closed. 15

Assuming that a train moving toward the right enters-the detector section DE, the shunt across the rails due towheels and axles of the train deenergizes relay TRI; causing front contact 20 to open and thus to deenergize magnet XRI 20 of the interlocking relay. Front contact ll-l2 opens because the associated armature assumes its fully released position. It should be noted that the opening of front contact I I-l2 opens the circuit for relay TRZ which thereupon releases, 25 and, in-turn, opens the circuit for magnet XR2 at front contact 2|. The flagman contact 1-8 of magnet XRZ will not open, however, and the back contacts 'l9 and I6ll will not close because-of the interlocking feature referred to ac above. The backcontact l8-|9 will close, thus completing the circuit for signal S which now provides an indication at the crossing of the approach of the train.

The closing of back contact ll-l3 closes a 35 shunt around the rail joint 2 at location E whereby the train shunt remains effective in preventing the pick-up of relay TRI, and, consequently, the pick-up ofrelay XRl, until the train passes beyond the" rail joint at location F. This insures 40 that the warning device at the crossing will remain in operation until the rear end of the train completely" clears the crossing.

When'the train completely clears section DF, the energizing circuit'for relay TRI will again 45 become effective; Thiscircuit has already been traced andincludes source 3 at location D, wires 4, 5, and6; and fiagman contact 'l-Bbf relay XRZ'." 'I'hereason for maintaining front contact 'l-8'closed' in spite of the deenergized condition 5 of the magnetXRZ will now become apparent, since the closed'condition of this contact makes it possible to pickup the rear track relay after the train clears the crossing. The pick-up of relay lTR'causes relay XRI to pick up over contact 20, which latter relay prepares a pick-up circuit for relay IE2 at contact I l|2. As soon as the train completely clears section FG, relay TRZ becomes energized from source 3 at location G, over the circuit previously traced for this relay. The closing of contact 2| of relay TRZ causes relay XRZ tobecome energized. The ap paratus is now restored to the normal condition in which it is illustrated in the drawing.

The sequence of operation for a train approaching the crossing in the reverse direction, that is, from right to left, is similar to that described above, and need not be repeated in detail. It will be sufiicient to state that relay TR2 will first release, followed by relays XR2 and TRI. Relay XRI will then be deenergized but its flagman contact H--|2 will remain. closed and its back contact ll-l3 will remain open due to the looking feature which was brought into play by the prior release of relay XR2.

Referring now to Fig. 2, the apparatus of this figure functions in a similar manner to that described in connection with Fig. 1, but itwill be noted that, in Fig. 2, relays TR! and TR21 are eliminated and the interlocking relay XR itself performs the functions of the track relays. A further difference is that instead of opening the circuit of the forward relay upon shunting of the rear relay due to the entry of a train into the detector section, the rear relay causes a shunt to be applied across the forward relay.

Normally, with the section DG unoccupied, both relays XR! and XR2 are energized. The circuit for relay XRl includes source 3 at location D, rail 1, wire 22, winding of relay XRI, wires 23 and 24, and rail la, back to the source 3. A similar cricuit for relay XRZ includes source 3 at location G, and wires 25, 26, and 21.

When a train moving toward the right enters the detector section DE, relay XRI will release due to the train shunt and will initiate the warning at the crossing due to the closing of its back contact i8-l9. The closing of back contact II-l3 places a shunt around the rail joint at location E, as in Fig. 1, to extend the length of the track circuit so as to include the highway and thus to insure that relay XRI will not pick up until the train fully clears the crossing. Furthermore, the closing of back contact 28 closes an obvious shunt path around the winding of relay XR2 whereby this relay is deprived of energy. The back contacts of relay XR2 will not close, however, and the flagman contact 293i3 will not open because of the locking feature. Therefore, the auxiliary shunt path around relay XRZ will remain effective, over contact 29-30, until such time as relay XRl picks up. This will occur when the rear end of the train passes location F.

When this happens, the train shunt will be removed from the track circuit section DF and relay XRI will receive energy over its previously traced energizing circuit. Thereupon, the warning will be discontinued and the auxiliary shunt will be removed from around relay XRZ. As soon as the train completely clears section F-G, relay XR2 will pick up over its obvious energizing circuit, whereupon the apparatus will be restored to its normal condition. The operation for a train movement from right to left will be obvious from the foregoing description.

The auxiliary shunt path for magnet XR2 insures that when a light engine passes rapidly from track section DE to track section F-G, magnet XRZ will become deenergized before magnet XRE becomes energized, thus insuring that the interlocking feature of relay XR will function properly,

It should be noted in connection with Fig. 2 that should both relays XRI and XRZ release simultaneously, for any reason, an inoperative failure of the highway crossing apparatus will not result because, as soon as normal conditions are reestablished in the section, relays XRI and XRZ will pick up again. In Fig. l, on the other hand, the simultaneous release of relays XRI and XRZ might cause both relays TR! and TRZ to release, whereupon relays XRI and XR2 would both remain released and would not restore themselves automatically to the normal or picked up position.

Referring now to Fig. 3, the apparatus of this figure is similar to that of Fig. 2 but comprises a slightly modified circuit arrangement which, however, provides substantially the same type of protection as is provided by the apparatus of Fig. 2. In Fig. 3, when a train enters the detector section DE from the left, relay XRI releases and closes a shunt path around the rail joint at E over wire 3|, back contact 32, wires 33 and 34, flagman contact 3536, and wires 31 and 38. A shunt is also placed around the winding of relay XR2, as in Fig. 2, over wire 39, back contact lil, wires H and 34, fiagman contact 3536, and wire 31. It will be apparent, therefore, that in Fig. 3, the various operations and their sequence are similar to those previously described for Fig. 2. Consequently, the operation of the apparatus will be clear without further detailed explanation.

From the foregoing description, it will be apparent that I have provided highway crossing protection involving a minimum of apparatus, yet providing a high degree of safety and reliability in its operation.

Although I have herein shown and described only three forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination with a section of railway track intersected by a highway, two track circuits for said section, one at either side of the highway, an interlocking relay having two magnets controlled by traflic conditions in said two track circuits respectively, means controlled by one of said two magnets effective when the track circuit associated therewith is occupied for extending said associated track circuit to include the highway, and means including a flagman contact of said other magnet effective during the occupancy of said associated track circuit for deenergizing the other magnet of said interlocking relay.

2. In combination with a section of railway tive condition of said interlockingrelay in the event that both of said two magnets release simultaneously.

3. In combination with a section of railway track intersected by a highway, two track circuits for said section, one at either side of the highway, an interlocking relay having two magnets receiving energy from said two track circuits respectively, means controlled by one of said magnets for at times extending the track circuit associated therewith to include the highway, and means governed by said one magnet and including a front contact of the other magnet for at said times controlling the energization of the other of said magnets.

4. In combination with a section of railway track intersected by a highway, two track circuits for said section, one at either side of the,

' highway, an interlocking relay having two magnets receiving energy from said two track circuits respectively, and means effective when one of said magnets is deenergized by the entry of a train into its associated track circuit for controlling the length of said associated track circuit and for closing a shunt path around the other of said two magnets over a front contact of said other magnet.

V 5. In combination with a section of railway track intersected by a highway, two track circuits for said section, one at either side of the highway, an interlocking relay having two magnets receiving energy from said two track circuits respectively, means including a back contact of one of said magnets for extending the track circuit associated with such magnet to include the highway, and means including a back contact of said one magnet and a front contact of the other of said magnets for closing a shunt path 7 around said other magnet.

6. In combination with a section of railway track intersected by a highway, two track circuits for said section, one at either side of the highway, a track relay for each of said two track circuits, an interlocking relay, circuits for energizing one and the other magnet of said interlocking relay controlled respectively by one or the other of said track relays, means controlled by one magnet of said interlocking relay for extending the associated track circuit to include 60 the highway, and means including a flagman contact of said one magnet for controlling the energization of said other track relay.

7. In combination with a section of railway track intersected by a highway, two track circuits for said section, one at either side of the highway, a track relay for each of said two track circuits, an interlocking relay, circuits for energizing one and the other magnet of said interlocking relay controlled respectively by one or the other of said track relays, means for energizing said one track relay from its associated track circuit including a flagman contact of said other magnet of the interlocking relay, means for energizing said other track relay from the track circuit associated therewith including a fiagman contact of said one magnet of the interlocking relay, and means controlled by said one magnet for extending the associated track circuit to include said highway.

8. In combination with a section of railway track intersected by a highway, two track circuits for said section, one at either side of the highway, an interlocking relay, a track relay for each of said two track circuits and energized over a flagman' contact of one and the other magnet respectively of said interlocking relay, circuits for energizing one and the other magnet of said interlocking relay each including a front contact of the respective track relay, and means including a back contact of one or the other of said two magnets for extending the associated track circuit to include said highway.

9. In combination with a section of railway track intersected by a highway, two track circuits for said section, one at either side of the highway and each terminated by a rail joint near the highway intersection, an interlocking relay having its two magnets controlled respectively by traflic conditions in said two track circuits, means including a back contact of one of said magnets and efiective when the associated track circuit is occupied for closing a shunt path around one of said rail joints to thereby extend said associated track circuit to include the highway, and means including a fiagman contact of said one magnet for controlling the track circuit associated with the other magnet to thereby modify the control of the other of said magnets by its associated track circuit.

EDWIN J. SCI-IAEFER. 

